How to identify Iron Ore

To correctly identify Iron Ore (Hematite or Goethite (likely a mix)), check each of these features in order. Many rocks and minerals look alike, so cross-reference multiple properties before deciding.

Step-by-step identification

1. 1

   Color

   Overall color and any zoning or banding

   Hematite: Red, reddish-brown, steel-gray, black. Goethite: Yellowish-brown, dark brown, blackish-brown.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Hematite: Metallic (specular hematite), dull to earthy. Goethite: Adamantine to dull, earthy.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Massive, earthy, oolitic, pisolitic, botryoidal, micaceous (specular hematite).

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Hematite: Rhombohedral, tabular, botryoidal, massive, micaceous. Goethite: Orthorhombic, acicular, fibrous, botryoidal, stalactitic, massive, earthy.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Hematite: No true cleavage, but parting may be observed along rhombohedral planes. Goethite: Perfect cleavage on {010}, but rarely observed in massive forms.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Banded Iron Formations (BIFs), lateritic weathering profiles, hydrothermal veins, sedimentary deposits (e.g., bog iron).

Key Facts

Hardness

Hematite: 5-6.5 on Mohs scale; Goethite: 5-5.5 on Mohs scale

Specific Gravity

Hematite: 4.9-5.3; Goethite: 3.3-4.3

Crystal System

Hematite: Trigonal; Goethite: Orthorhombic

Color

Hematite: Red, reddish-brown, steel-gray, black; Goethite: Yellowish-brown, dark brown, blackish-brown

Luster

Hematite: Metallic, submetallic, dull, earthy; Goethite: Adamantine, silky, dull, earthy

Transparency

Opaque

Fracture

Hematite: Uneven to subconchoidal; Goethite: Uneven

Cleavage

Hematite: None (parting common); Goethite: Perfect on {010} (rarely observed)

Composition

Hematite: Iron(III) oxide (Fe2O3); Goethite: Iron(III) oxyhydroxide (FeO(OH))

Physical characteristics

• Crystal Habit: Hematite: Rhombohedral, tabular, botryoidal, massive, micaceous (specularite), oolitic, earthy. Goethite: Acicular, fibrous, botryoidal, stalactitic, massive, earthy.
• Cleavage Type: Hematite: None (parting on {1011} is common); Goethite: Perfect on {010}, but often not visible in massive forms.
• Fracture Type: Hematite: Uneven to subconchoidal; Goethite: Uneven.
• Tenacity: Brittle
• Luster Type: Hematite: Metallic, submetallic, dull, earthy; Goethite: Adamantine, silky, dull, earthy.

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